Search

Diffusion of Ga in relaxed intrinsic Si1-xGex layers has been determined at 907 °C within the whole composition range. Based on current results and available systematic diffusion data for Si, Ge, and Si1-xGex alloys, it is suggested that Ga diffusion is interstitialcy mediated in Si rich materials and vacancy mediated in Ge rich materials. The results indicate that the dominating diffusion mechanism change takes place at x∼0.6. [ABSTRACT FROM AUTHOR]

Abstract: Diffusion of implanted 57Co in ZnO has been determined in the temperature range 660–950°C using the modified radiotracer technique. The diffusion was found to follow the Arrhenius type relation with an activation enthalpy of (2.9±0.3)eV and a pre-exponential factor of 3×10−4 m2/s. Supported by diffusion data and conclusions provided in the literature, it is proposed that cobalt diffuses substitutionally in ZnO. [Copyright &y& Elsevier]

Examines the diffusion of aluminum in polycrystalline ion-implanted α-titanium in the temperature range 600-850 degree celsius using ion-beam techniques. Method used in monitoring the time-dependent concentration profiles; Effect of the implantation energy and implanted dose on the diffusivity of aluminum; Process used to investigate the possible effect of radiation damage to the migration of the diffusing aluminum.

The charge state of mobile vacancy-impurity complexes in germanium was studied via the effect of p-type (Ga) doping on Ga and Sn diffusions. Tin diffusion retards significantly as a function of doping concentration suggesting diffusion dominated by negatively charged vacancy-Sn complexes. Gallium diffusion is practically unaffected by doping, suggesting diffusion dominated by vacancy-Ga complexes having the same charge state as isolated, negatively charged Ga ions. The evident two orders of magnitude higher diffusivity of group V elements in germanium than of group III and IV elements can be well explicated by means of the present findings. [ABSTRACT FROM AUTHOR]

Abstract: Migration kinetics of low-concentration implanted 7Be in glassy carbon has been studied by the modified radiotracer technique at temperatures 1285 °C and 1340 °C. The annealed sample concentration profiles show two distinctive components: (i) Main profile broadening assigned to beryllium trapping in defects during annealing. (ii) Tail parts on both sides of the profile maximum related to faster migration. Of the latter the profile representing bulk diffusion lies on the region free of defect influence and is well described by concentration-independent diffusivity. The features of the concentration profile broadening towards the sample surface indicate partial Be trapping in defects upon annealing. Diffusion coefficients for Be migration in the damaged and defect-free material are provided. It is concluded that light impurity atom diffusion in glassy carbon is of the same order of magnitude as diffusion in diamond. [Copyright &y& Elsevier]